India joins global effort to detect gravitational waves with new LIGO venture

“Indian S&T will leap-frog in a number of cutting-edge frontiers of great national relevance, in particular quantum-sensing and metrology,” said Tarun Souradeep, director of the Raman Research Institute, Bengaluru, and former spokesperson of LIGO-India to The Hindu.

Gravitational waves are considered to be ripples in the fabric of spacetime. These are emitted by astronomical objects such as black holes and neutron stars. 

Although first predicted by Albert Einstein in 1916, the first indirect evidence of gravitational waves would not be recorded until 1974, when orbital decay of the Hulse–Taylor binary pulsar was observed.

In 2015, gravitational waves were detected by LIGO (laser interferometers), a scientific achievement whose significance was recognized by winning the Nobel Prize in Physics in 2017.

LIGO, a giant L-shaped instrument, consists of two 4 km long arms- concrete structures that protect vacuum tubes residing inside. Each arm shoots laser pulses simultaneously that bounce off a mirror at the end and return to the vertex. A detector checks if these return at the same time. 

The presence of gravitational waves results in a slight delay in the return of these pulses, enabling researchers to study and record them.

Although the two existing LIGOs- in Louisiana and Washington in the US- can study gravitational waves, there is a need for multiple detectors- ideally three or more- to localize the location of a source in the sky. More of these are being set up and upgraded in Italy and Japan.

The LIGO-India project will be built with a memorandum of understanding (MoU) with the National Science Foundation, US, along with several national and international research and academic institutions.

“The LIGO-India Observatory will enable dramatic astronomy and astrophysics returns eagerly anticipated from the global network of LIGO Gravitational wave detectors in the coming decade,” said an excited Dr. Souradeep.